To save power, it is conventional to transmit data using a “low-swing” differential voltage signal. The signaling is deemed to be low swing in that the differential voltage is less than the power supply voltage. For example, the power supply voltage may be 1 V but the differential voltage for a low-swing differential voltage signal may be 300 mV or even lower such as 240 mV. Since the low-swing differential voltage signal is not driven “full rail” to the power supply voltage, power is conserved.
To provide the reduced voltage for a low-swing differential transmitter, it is conventional to use a low-drop-out (LDO) regulator. The LDO regulator acts as a resistor such that it introduces a power loss in converting the power supply voltage to the reduced voltage used for the low-swing differential signaling. This power loss gets repeated in that it is conventional to transmit a multi-bit-wide digital word using a corresponding plurality of low-swing differential signals. Each signal draws its own current from the LDO regulator that introduces its own corresponding power loss.
Accordingly, there is a need in the art for differential low-swing signaling with reduced power consumption.